WHEN MATT MULLICAN is invited to lecture on his artistic practice to a large group at a museum or school, he typically begins his presentation by affixing a number of images to the wall behind him: first, a photograph of one person, followed by a comic-strip rendering of a second person; then two stick figures (one framed, the other unframed), an abstract sign for the human body (akin to those found at crosswalks or on bathroom doors) and a similarly spare icon denoting a head and chest (think of the cropped international symbol for customs officers at airports); and finally, a circle, a square, and a triangle assembled together in a loose configuration of parts. Each of these individual pictures, Mullican says, is named “Glen.” (In truth, however, only the photograph depicts anyone recognizable as such, whether the visage of astronaut John Glenn, actor Glenn Ford, or some other